United Airlines offers roundtrip flights to Hawaii from select cities in the U.S. for as low as $489, as listed at Travelzoo. (A roundtrip purchase is required.) That's the lowest price we've seen for flights to Hawaii via United since October. (Rates started at $380 roundtrip previously, since expired.) Flights are valid on select days through June 9 and also between August 15 and December 14. Advanced purchase and travel day requirements vary depending on the route selected. Additional taxes and fees apply. Deal ends November 14.